August 2021

Concussion Series: Part One

Assessing the impacts and risk of concussion and head knocks in the NRL.

This is the first part in our three part series looking at concussion, its place in professional sport, how it’s being treated and what the research currently says. Subscribe to get full access to the series over the next three months.

Concussion. You’re probably picturing what concussion is right now. Maybe it’s a player stumbling around after a head knock. Maybe a boxer laid out on the canvas. You might even be thinking of the long term damage concussion is said to have caused and is causing.

Concussion has become something of a dirty word in professional sport, particularly in rugby league.

It’s spoken about as the cause of many brain diseases or the reason for mental impairment.

Concussion isn’t new to sport, the long-term damage it can cause isn’t new either. 

But concussion and its after effects are more nuanced than has often been reported.

In this series we will be looking at the origins of concussion, its relevance and impact on sport, how it is currently being treated, what research is underway and how it could be treated and assessed in the future.


Concussion in history

Brain injury has been recognised for thousands of years. In ancient times there was an understanding of brain trauma, however no distinction was made between a concussion, whose symptoms are transient (the patient recovers on their own), and serious traumatic brain injury. 

According to a report published in 2001 by the American Academy of Neurology, the first recognition of concussion as its own condition was made in the 10th century by the Persian physician Rhazes. 

A Renaissance physician by the name of Lanfrancus labelled the condition brain “commotion” in the 13th century. During the 18th century hypotheses were being developed about the causes of concussion with more detailed, evidence-based hypotheses being made in the 19th century.

In 1839 Guillaume Dupuytren distinguished between unconsciousness and concussion.

Further research from Seminars in Pediatric Neurology published in 2019 went into further detail. The researchers found that James Crichton-Browne, a Scottish doctor and neurologist, once stated in the 1870s that after receiving one concussion, a person should avoid a second for the rest of their life.

Concussion in sport

In more modern settings, the early to mid 1900s saw a greater concentration and concern surrounding concussion.

In 1928 the effect of repeated concussions in boxers was first recognised and labelled “punch drunk”.

In 1937 the condition was labelled “dementia pugilistica” due to the symptoms appearing in mostly boxers. At the time, boxers participated in hundreds of fights with poor equipment and were more susceptible to punches to the head than they are today.

Investigating the role concussion has played in sport is Professor Chris Levi from the University of Newcastle. 

He says much of what he is investigating now, we have known about for a while but it’s only recently there has been a concerted effort to really unravel the mysteries of concussion.

“It’s been recognised for centuries that a mild head impact can result in transient mental impairment but the longer term complications of repeated concussion weren’t described until the 1920s in boxing. 

“Dementia pugilistica which was recognised to be a complication of repeated concussions in boxers and that really is this same entity (referring to CTE) that’s sort of resurfaced a hundred years later. So it’s been recognised for a hundred years. It’s not new,” Professor Levi says.

One of the contributors to a lack of investigation across the sporting world, was the belief the condition only affected boxers due to the amount of concussions and blows to the head they sustained across their careers.

“It was thought to be exclusively boxing for a period of time, however in the non-sports concussion space, the consequences of mild or moderate traumatic brain injury and their association with dementia has been recognised for a long time, since we’ve known that traumatic brain injury is a risk factor for later in life dementia, outside sports concussion, for decades.”

Development of CTE

CTE is the acronym for the medical term Chronic Traumatic Encephalopathy. The term itself was borne out of dementia pugilistica following research by British neurologist Dr MacDonald Critchley in 1949.

Critchley was investigating the prevalence of CTE in boxers and it’s believed this is the first time the phrase was publicly coined.

Professor Levi explains that CTE is, itself, not a condition, but a construct grouping together a range of factors and symptoms.

“CTE is a neuropathological construct. So it’s not a condition that can be diagnosed in life because there is a very broad spectrum of dementias where the clinical features overlap quite a lot.”

CTE broke into the public consciousness in the mid-2000s when Dr Bennet Omalu produced case reports on two retired NFL players he had performed autopsies on, and found both to be suffering from the condition at their time of death.

Brain scans showing the amount of tau protein (contributor to CTE) in the brains of NFL players compared with non-football players as documented in the New England Journal of Medicine.

Professor Levi though, says the original pathology from Dr Omalu’s reports has evolved and we now know that the brain injuries and symptoms Dr Omalu described, are present across a whole cohort of patients, not just in those who have sustained concussions.

“The description was of this pathology that was, at that time, thought to be specific but the issue with that is that this pathology which was described initially by the group and further cases identified, has later been recognised to be not specific to concussion.

“We see it in so called normal people, in autopsies. We see it in some people with epilepsy when we do brain surgery for epilepsy. We see it in some people with Parkinson’s, we’ve seen it in some people with Motor Neurone Disease type pictures. So it’s not necessarily specific.”

The concern in some expert circles surrounds repeated impacts to the head instead of concussions.

The difference between concussion and head impacts

Dr Chris Nowinski, CEO of the Concussion Legacy Foundation and co-founder of the Boston University CTE Center in the United States is approaching the issue from a somewhat unique position among researchers.

Before his roles as a concussion expert and researcher, Dr Nowinski was a professional wrestler in the WWE. He retired in 2003 after 12 months of post-concussion syndrome.

He says that the research in America is focussing on the cumulative effects of multiple blows to the head across a sporting career.

“We’re (the US researchers) talking about years of exposure. That’s where we’re seeing a direct line between your risk of developing CTE and the severity of CTE and we don’t necessarily see the guys who have had concussions and developed symptoms over the years be worse than others. So when people say they have concussions and “I’m worried about the effect”, what they’re really saying is, “I’ve been exposed to rugby for a few years and I’m worried about effects”.

“If you’ve had a handful of concussions it doesn’t mean you’re going to have problems. But if you’ve played 25 years of rugby, whether or not you’ve had concussions, you’re at risk of long term effects. You’re at risk for CTE… Concussions in the absence of other head hits do not appear to cause CTE,” says Dr Nowinski.

Drawing on his own experience as a college football player and professional wrestler, Dr Nowinski says he knows he was concussed on multiple occasions, but also that he received harder blows to the head which didn’t result in a concussion.

The lesson he draws from this is that it’s likely those blows to the head which are termed “sub-concussive” are the ones that are more likely to lead to CTE in time due to the fact they are more often experienced by athletes.

“The computer models of twisting brains show that the greatest stress to the brain tissue is exactly where we find the beginnings of CTE. That’s the problem with a twisting brain. So you can get hit really hard, twist your brain really hard. I can’t remember the hardest hits, but I can vaguely remember the ones that changed the symptoms I had. I know I was hit harder many, many times, it just didn’t cause symptoms. 

“So there is some randomness we don’t quite understand. So the idea is that you have more opportunities to start CTE with more hits and you may be starting CTE multiple times. One lesion from one hit when you’re 15 and another lesion from another hit when you’re 18 and they both start spreading,” Dr Nowinski explains.

Professor Levi however urges caution in drawing a distinct link between impacts to the head and the development of mental impairment conditions later in life, saying more research is needed. 

He says the term “sub-concussive blow” is currently inaccurate as there is no clear, definitive definition of what sub-concussive means when looking at the research.

“This sub-concussive thing, I think that’s a pretty nebulous concept. I don’t know what that is. You could imagine, you or I could bump their head on the chook pen, and that could be sub-concussive. I think as a term, it’s such an unhelpful term, it’s not defined as anything clinical. 

“Whereas a concussion has a clinical definition of brief transient neurological impairment that resolves within a period of minutes to hours, to at the most a few days and then there’s a post-concussive syndrome which can be a complication of that.”

What is clear though, is that there is a concern both in the medical community and sporting leagues about the long-term effects of multiple blows to the head during an athletic career.

Previous concussion treatments

Unfortunately, these concerns have only been addressed in recent years. Barely a decade ago it was commonplace in the NRL to see a player hit in the head and remain on the field.

It was accepted policy to remove the player, briefly assess them off the field and then allow them to return.

Think of Sam Burgess in the 2014 NRL grand final. While the images of a crying Burgess on the field at full time with a smashed face have become seen as his toughness, in today’s NRL, he’d likely have been removed from the field for a head injury assessment.

The HIA protocols existed in 2014, however they weren’t as strictly enforced given Burgess never left the field following his opening tackle collision with opposing Englishman James Graham.

In past eras it was completely normal to leave a player who had been concussed out on the field. It was a mark of toughness and durability.

That’s despite some doctors raising concerns over this practice at the time. As reported by The Sydney Morning Herald’s Adrian Proszenko when he spoke to former Parramatta Eels medical expert Dr Peter Manollaras who said he had concerns over repeated concussions during the 1980s.

“It wasn’t discussed very much at the time, but I did notice quite a lot of our first-graders and lower-grade players were having trouble getting back following a head knock,” Dr Manollaras said.

“They weren’t functioning as well as they should have been and it occurred to me that the brain needed more time to recover. Of course, in those days they wanted the players back on the field as soon as possible.

“In the case of head injuries, I made a decision to rest them for at least a week. I tried my best to not let them come back too early.”

Treatment and assessment of concussion has come a long way since Dr Manollaras was involved in rugby league and sporting leagues around the world have adopted their own policies to address the issue.

It’s hoped that the game can be made safer without overly impacting on the physicality and ferocity of the sport.

In parts two and three we will be looking at the research conducted in the past 15 years on concussion, how the NRL and other sporting bodies have begun to address the issues raised and what researchers are looking at as the future of concussion diagnosis and treatment.


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